As Kerrigan channeled Ouros's power, she was assaulted by void thrashers. She was able to use her newfound power to annihilate them, but such a power would stall her transfer. Kerrigan's allies set up defensive positions around her, while shadows of the Void came in from all directions. Raynor was forced to send forces to reinforce them before they fell. More void thrashers were summoned to assault Kerrigan, but were quickly dispatched.

Raynor held his position, and Kerrigan managed to channel the power, sending a blast that destroyed the shadows of the void in the area. Kerrigan ordered Zagara to take control of the Zerg Swarm, and to remember the lessons she had taught her.[1]

Ouros departed the last of his essence to Kerrigan, stating the Infinite Cycle had now ended, and died. With the last of the xel'naga essence, Kerrigan changed form into that of a flaming angel, brimming with power. She sent a vision to Raynor, saying that the moments they had together would always be with her, but that they had to go. Raynor told her to finish this fight, and Kerrigan flew off to face Amon.[2]

In this mission, the player spawns as the terran in the center, and has defenses on the western approach. Allies hold the east and southern approaches, but in limited number. The goal is to defend Kerrigan, and to keep allied forces alive as long as possible in order to use them as a buffer. Kerrigan can be used in a similar fashion to the Drakken laser drill from The Dig which includes slowing down her evolution as she uses it, but given the larger number of enemies it is recommended that she only be used for very high priority targets. First priority should be taking the expansion west of the starting base, in order to get the extra resources needed for a defense.

Wings of Liberty campaign units are available, and as such mercenaries should be called down whenever possible. Every single mercenary type is available. The units and structures have the following upgrades from the campaign:

All infantry has Stimpacks

Marines have the shield for a bonus 10 health

Maurauders have Concussive Shells for the AoE slowdown

Medics have Stabilizer Medpacs for more effective healing

Reapers have Combat Drugs for fast healing out of combat

Spectres have upgraded cloaking devices that cost no energy

Siege Tanks have Shaped Charge for reduced friendly fire damage

Goliaths have the Ares class targeting system for improved range

Medivacs have Advanced Healing AI to heal 2 targets

Vikings have Ripwave Missiles for AoE damage

Banshees have Shockwave Missile Batteries for AoE damage in a line

Science Vessels are available at the Starport

Bunkers have Shrike Turrets and 2 additional space

Silos have instant calldowns

All buildings have the self-repair to 50% health upgrade

Even on a normal difficulty level you will find that on their own your two NPC allies are rather "stupid" commanders and do NOT build well defensively, so you will need to send them a great deal of help in order to get the shown bonus objectives of not letting your ally bases die. Siege tanks, bunkers and missile turrets should defend the terran and protoss bases, while a mobile force should defend the zerg base. Structures cannot be built on the creep, but they will provide a stronger defense, and as Zagara will respawn when slain she does not need as much defense until later in the mission. Artanis will come back to full health upon taking fatal damage due to his resurgence ability, but if killed a second time while resurgence is on cooldown he will not respawn. This will usually happen early in the mission, especially on higher difficulties, and as such the protoss base is the more vulnerable.

Use Kerrigan to take out void thrashers or high priority targets like brood lords that outrange static defenses. Try to avoid overusing it, as the last pushes are brutal and can come down to seconds.

On Brutal mode, bunkers will prove ineffective against the swarms of enemies that attack you due to their insufficient durability. It is better to make walls with planetary fortresses with siege tanks and SCVs behind them and nearby missile turrets. Vikings should also be used for anti-air defense (and killing colossi), as missile turrets will be regularly torn apart by enemy ground forces.

One unit that can prove particularly useful in this mission is the spectre. The enemies that attack you will have no detectors, and since the spectres have access to permanent cloaking, they can fire without fear of direct retaliation (only needing to worry about splash damage). A force of spectres can prove highly effective at helping to defend Zagara's base, especially if you use their Psionic Lash attack on heavier targets.

If there is need for extra vespene gas, allies' extractors and assimilators can be destroyed and automated refineries can be built in their place. As the AI does not actually need to mine resources, this will not inhibit their ability to build.

If trying for the Purity of Purpose achievement, note that as long as Kerrigan's beam does not kill an enemy unit, it does not count against the limit. Therefore, her beam can be used to soften a target, leaving it nearly dead and letting other units finish it off. This can be very tricky to manage, however, due to her beam's sheer damage.